Inadequate Dietary Calcium and Vitamin D Intakes in Renal-Transplant Recipients in Ireland

Objective

To quantify the dietary calcium and vitamin D intake in adult renal-transplant recipients attending at a large teaching hospital in Ireland for follow-up.

Setting

Outpatient renal-transplant follow-up clinic.

Subjects

Fifity-nine adult renal transplant recipients (58% male) with a mean age of 46 years, a median transplant duration of 6 years, and a mean estimated glomerular filtration rate (eGFR) of 50 mL/min per 1.73 m². Fifty-three percent were at National Kidney Foundation stage 3 chronic kidney disease, and 14% had stage 4 chronic kidney disease.

Intervention

This cross-sectional, observational study used a tailored food frequency questionnaire specific for calcium and vitamin D intake in Irish adults, which was completed during a face-to-face interview with each subject.

Main Outcome Measure

The main outcome measure was the average daily dietary and supplemented calcium and vitamin D intake.

Results

The median interquartile range (IQR) dietary calcium intake was 820 mg/day (range, 576-1,177 mg/day), and was similar in men and women (recommended intake ≥1,000 mg/day in adult men and nonmenopausal adult women, ≥1,500 mg/day in menopausal women). Five participants received calcium supplementation. Overall, 59% of men and 64% of women had total calcium intakes below the recommended amounts. The median IQR estimated dietary vitamin D intake was 5.2 μg/day (range, 2.4-6.4 μg/day) in women, and 4.6 μg/day (range, 2.2-6.6 μg/day) in men (recommended intake, ≥10 μg/day). Six subjects received vitamin D supplementation. Total vitamin D intakes were suboptimal in 91% of men and 87% of women. Dietary calcium and vitamin D intakes significantly correlated with each other, but neither was significantly related to eGFR category, and was similarly low in both presumed menopausal women and in the initial year posttransplantation.

Conclusion

These findings suggest that dietary and total calcium and vitamin D intakes in adult renal-transplant patients are in many cases inadequate.